Windows Phone posted the largest year-over-year increase among the top five smartphone platforms, and in the process reinforced its position as the number 3 smartphone operating system. Driving this result was Nokia, which released two new smartphones and grew its presence at multiple mobile operators. But beyond Nokia, Windows Phone remained a secondary option for other vendors, many of which have concentrated on Android. By comparison, Nokia accounted for 81.6% of all Windows Phone smartphone shipments during 2Q13.

Over the past 12 months, Windows Phone went from 3.1% market share to 3.7%. This means that while shipments of Windows Phone devices are growing, they're barely growing any faster than the industry as a whole. Still, it's crazy to see there's less than a 10 percentages points difference between Windows Phone and iOS.

Another potential problem is that Microsoft is effectively entirely dependent on Nokia. If Nokia falters, Windows Phone falters. Other vendors have essentially lost all interest in the platform, and as such, Microsoft has a a very strong impetus in keeping Nokia going. Still, I'm pretty sure that the Surface phone is ready to go at a moment's notice.

In terms of US smartphone sales Andoid is 51% and iOS is 43%. When you look at things like App downloads and web browser statistics it is again pretty close.

Of course, if you measure different things then you get different results. IDC is looking at worldwide smartphone share, and their numbers usually roughly match those from the other big analyst houses (Canalys, Gartner, Strategy Analytics).

If you look at US market share like e.g. comScore does, then you will of course see something very different: A market where phones are heavily subsidized by carriers through postpaid contracts, which is not common in most other parts of the world.

And if you look at usage statistics then you will measure installed base and behavior of the demographic that uses a particular platform.